Thomist solution to the problem of love -- Remarks on the elements of the Thomist solution in Greek and medieval thought -- Two medieval sketches of the physical theory -- First characteristic : duality of the lover and the beloved -- Second characteristic : the violence of love -- Third characteristic : irrational love -- Fourth characteristic : love as the final end -- Appendix 1: The postulation of the problem of love in the first scholastics -- Appendix 2: The formal identification of love and understanding in William of St. Thierry.